Corrosion resistant nickel base alloy



OFFICE v UNITED I STATES FATE CORROSION RESISTANT NICKEL BASE ALLOYClaude R. Bishop, Niagara Falls, N. Y., assignorto Haynes StelliteCompany, a corporation of Indiana No Drawing. Application August 24,1939,

Serial No. 291,672

5 Claims. (Cl. 75-170) The invention relates to corrosion resistantalloys and particularly to nickel-base alloys hav- Corrosion rate inmilliing improved corrosion resistance; l I g gzf gg ggg g;

Nickel-base alloys containing silicon, with or CmWsltwnfiemamder N1)aerated 10% aqueous without additions of aluminum or copper or mix- 32 56 temperature tures thereof, are particularly resistant to many vcorrosive media, notably including hot aqueous solutions of hydrochloricacid. Alloys of the Si Cu Al Sb First Second Thud foregoing type aredisclosed in Patents 1,514,064 1 and 1,753,904, issued to A. J. Mandelland C.

10 Plummer, respectively. While extensive use has 10- been made of theexcellent resistance of such 7.8 3 None None 0.76 0.77 alloys tocorrosion by hydrochloric acid, there is g Y3: 8& 8-3 8-2 a demand foralloys having even greater resist- 11' 3.4 None 6.5 0144 0: 27 0:22 tothis we 2-: 21 is: 3-2: 8-33 h (P)- 41 15 The principal object of thisinvention is to pro- 1013 31 1 None 715 0123 0127 o 15 vide anickel-base alloy having improved corro- 8:? 3:3 g3 3; 3'32 3- EI; sionresistance, particularly to hydrochloric acid, 10.8 13.7 3.7 1.4 013s0148 v) and good physical properties. This and other objects areattained in the present invention by Not tested.

the applicationpf discfvery m the addition The corrosion rates shown inthe above table 20 @ntlmony, wfthm certaln defimt? compPsitlon weredetermined by completely immersing the limits, greatly improves thecorrosion reslstance specimen in the acid mm indicated therein a ot Pope s of the nickel-base y and maintaining that solution at constant temAlloys included in the invention contain silicon perature for theperiods of time indicated. The

in aproportion between 3% and 14%, preferably loss in weight wasdetermined and reported as between 6% and 11%; antimony in a proportionthe number of milligrams dissolved per square between 0.02% and 10%,preferably between 0.3% centimeter ,of surface per hour of time.

and 5%; copper in a proportion between 0.05% The addition of 0.3% to 5%antimony to the and 25%, preferably between 1% and 4%; w th alloysdescribed herein, in accordance with the 0 or t t mi in proportionbetween preferred procedure of the invention, does not 0.02% and 5%,preferably between 0.5% a materially affect their mechanical properties,

3%; remainder nickel which may be partly r but greater proportions ofantimony, that is, be-

placed by cobalt or iron or both. In addition to tween 5% and 10%usually lower Strength the foregoing elements a small proportion of ofthe alloy somewhat However m 35 manganese may be present to improve thehot stance the alloys possess excellent corrosion reworkingcharacteristics of the alloy; slstance, and in apparatus constructedfrom alloys containing the greater proportions of anti- The followingtable indicates the composition of several representative alloys of theinvention mony proper allowance m the deslgn of such a aratus ma .mad t40 and also indicates the results of COIIOSlOIl tests g z i of g gg forthe 40 made on samples of those alloys and on samples I claim;

of alloys containing no antimony but otherwise 1 An alloy comprising ilii a, proportion similar to those of the invention. between 3% and 14%;copper in a proportion between 0.05% and 25%; aluminum in}. proportionbetween 0.02% and 5%; antimony ina proportion, between 0.02% and 10%,serving to impart improved corrosion resistance to the alloy; theremainder nickel.

2. An' alloy as defined in claim 1 in which the silicon is in a.proportion between 6% and 11%. 3. An alloy as defined in claim 1 inwhich the copper is in a proportion between 1% and 4%.

10 4. An alloy as defined in claim 1 in which the nickel.

CLAUDE R. BISHOP. l0

